x86: Handle {disp32} for (%bp)/(%ebp)/(%rbp)

Since (%bp)/(%ebp)/(%rbp) are encoded as 0(%bp)/0(%ebp)/0(%rbp), use
disp32/disp16 on 0(%bp)/0(%ebp)/0(%rbp) for {disp32}.

Note: Since there is no disp32 on 0(%bp), use disp16 instead.

	PR gas/26305
	* config/tc-i386.c (build_modrm_byte): Use disp32/disp16 on
	(%bp)/(%ebp)/(%rbp) for {disp32}.
	* doc/c-i386.texi: Update {disp32} documentation.
	* testsuite/gas/i386/pseudos.s: Add (%bp)/(%ebp) tests.
	* testsuite/gas/i386/x86-64-pseudos.s: Add (%ebp)/(%rbp) tests.
	* testsuite/gas/i386/pseudos.d: Updated.
	* testsuite/gas/i386/x86-64-pseudos.d: Likewise.

7 files changed, 92 insertions, 3 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 2bb068f343e..ebc99b6e9c6 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,14 @@
+2020-07-28  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR gas/26305
+	* config/tc-i386.c (build_modrm_byte): Use disp32/disp16 on
+	(%bp)/(%ebp)/(%rbp) for {disp32}.
+	* doc/c-i386.texi: Update {disp32} documentation.
+	* testsuite/gas/i386/pseudos.s: Add (%bp)/(%ebp) tests.
+	* testsuite/gas/i386/x86-64-pseudos.s: Add (%ebp)/(%rbp) tests.
+	* testsuite/gas/i386/pseudos.d: Updated.
+	* testsuite/gas/i386/x86-64-pseudos.d: Likewise.
+
 2020-07-27  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* doc/as.texi: Replace preceeded with preceded.
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 9ab841383c5..11d0e992f97 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -8151,7 +8151,12 @@ build_modrm_byte (void)
 		      if (operand_type_check (i.types[op], disp) == 0)
 			{
 			  /* fake (%bp) into 0(%bp)  */
-			  i.types[op].bitfield.disp8 = 1;
+			  if (i.disp_encoding == disp_encoding_32bit)
+			    /* NB: Use disp16 since there is no disp32
+			       in 16-bit mode.  */
+			    i.types[op].bitfield.disp16 = 1;
+			  else
+			    i.types[op].bitfield.disp8 = 1;
 			  fake_zero_displacement = 1;
 			}
 		    }
@@ -8196,7 +8201,10 @@ build_modrm_byte (void)
 	      if (i.base_reg->reg_num == 5 && i.disp_operands == 0)
 		{
 		  fake_zero_displacement = 1;
-		  i.types[op].bitfield.disp8 = 1;
+		  if (i.disp_encoding == disp_encoding_32bit)
+		    i.types[op].bitfield.disp32 = 1;
+		  else
+		    i.types[op].bitfield.disp8 = 1;
 		}
 	      i.sib.scale = i.log2_scale_factor;
 	      if (i.index_reg == 0)
diff --git a/gas/doc/c-i386.texi b/gas/doc/c-i386.texi
index 3813f5eb59d..8be708e7450 100644
--- a/gas/doc/c-i386.texi
+++ b/gas/doc/c-i386.texi
@@ -822,7 +822,7 @@ Different encoding options can be specified via pseudo prefixes:
 @samp{@{disp8@}} -- prefer 8-bit displacement.
 
 @item
-@samp{@{disp32@}} -- prefer 32-bit displacement.
+@samp{@{disp32@}} -- prefer 32-bit (16-bit in 16-bit mode) displacement.
 
 @item
 @samp{@{load@}} -- prefer load-form instruction.
diff --git a/gas/testsuite/gas/i386/pseudos.d b/gas/testsuite/gas/i386/pseudos.d
index 00c10a520b1..76aae367b44 100644
--- a/gas/testsuite/gas/i386/pseudos.d
+++ b/gas/testsuite/gas/i386/pseudos.d
@@ -288,6 +288,15 @@ Disassembly of section .text:
  +[a-f0-9]+:	0f 28 90 80 00 00 00 	movaps 0x80\(%eax\),%xmm2
  +[a-f0-9]+:	0f 28 90 80 00 00 00 	movaps 0x80\(%eax\),%xmm2
  +[a-f0-9]+:	0f 28 90 80 00 00 00 	movaps 0x80\(%eax\),%xmm2
+ +[a-f0-9]+:	8a 45 00             	mov    0x0\(%ebp\),%al
+ +[a-f0-9]+:	8a 45 00             	mov    0x0\(%ebp\),%al
+ +[a-f0-9]+:	8a 85 00 00 00 00    	mov    0x0\(%ebp\),%al
+ +[a-f0-9]+:	67 8a 07             	mov    \(%bx\),%al
+ +[a-f0-9]+:	67 8a 07             	mov    \(%bx\),%al
+ +[a-f0-9]+:	67 8a 07             	mov    \(%bx\),%al
+ +[a-f0-9]+:	67 8a 46 00          	mov    0x0\(%bp\),%al
+ +[a-f0-9]+:	67 8a 46 00          	mov    0x0\(%bp\),%al
+ +[a-f0-9]+:	67 8a 86 00 00       	mov    0x0\(%bp\),%al
  +[a-f0-9]+:	c4 e1 78 28 d7       	vmovaps %xmm7,%xmm2
  +[a-f0-9]+:	c4 e1 78 28 d7       	vmovaps %xmm7,%xmm2
  +[a-f0-9]+:	c4 e1 78 29 fa       	vmovaps %xmm7,%xmm2
@@ -316,4 +325,13 @@ Disassembly of section .text:
  +[a-f0-9]+:	0f 28 90 80 00 00 00 	movaps 0x80\(%eax\),%xmm2
  +[a-f0-9]+:	0f 28 90 80 00 00 00 	movaps 0x80\(%eax\),%xmm2
  +[a-f0-9]+:	0f 28 90 80 00 00 00 	movaps 0x80\(%eax\),%xmm2
+ +[a-f0-9]+:	8a 45 00             	mov    0x0\(%ebp\),%al
+ +[a-f0-9]+:	8a 45 00             	mov    0x0\(%ebp\),%al
+ +[a-f0-9]+:	8a 85 00 00 00 00    	mov    0x0\(%ebp\),%al
+ +[a-f0-9]+:	67 8a 07             	mov    \(%bx\),%al
+ +[a-f0-9]+:	67 8a 07             	mov    \(%bx\),%al
+ +[a-f0-9]+:	67 8a 07             	mov    \(%bx\),%al
+ +[a-f0-9]+:	67 8a 46 00          	mov    0x0\(%bp\),%al
+ +[a-f0-9]+:	67 8a 46 00          	mov    0x0\(%bp\),%al
+ +[a-f0-9]+:	67 8a 86 00 00       	mov    0x0\(%bp\),%al
 #pass
diff --git a/gas/testsuite/gas/i386/pseudos.s b/gas/testsuite/gas/i386/pseudos.s
index 19900dd7e59..bc18654ced0 100644
--- a/gas/testsuite/gas/i386/pseudos.s
+++ b/gas/testsuite/gas/i386/pseudos.s
@@ -293,6 +293,18 @@ _start:
 	{disp8} movaps 128(%eax),%xmm2
 	{disp32} movaps 128(%eax),%xmm2
 
+	movb (%ebp),%al
+	{disp8} movb (%ebp),%al
+	{disp32} movb (%ebp),%al
+
+	movb (%bx),%al
+	{disp8} movb (%bx),%al
+	{disp32} movb (%bx),%al
+
+	movb (%bp),%al
+	{disp8} movb (%bp),%al
+	{disp32} movb (%bp),%al
+
 	.intel_syntax noprefix
 	{vex3} vmovaps xmm2,xmm7
 	{vex3} {load} vmovaps xmm2,xmm7
@@ -322,3 +334,15 @@ _start:
 	movaps xmm2,XMMWORD PTR [eax+128]
 	{disp8} movaps xmm2,XMMWORD PTR [eax+128]
 	{disp32} movaps xmm2,XMMWORD PTR [eax+128]
+
+	mov al, BYTE PTR [ebp]
+	{disp8} mov al, BYTE PTR [ebp]
+	{disp32} mov al, BYTE PTR [ebp]
+
+	mov al, BYTE PTR [bx]
+	{disp8} mov al, BYTE PTR [bx]
+	{disp32} mov al, BYTE PTR [bx]
+
+	mov al, BYTE PTR [bp]
+	{disp8} mov al, BYTE PTR [bp]
+	{disp32} mov al, BYTE PTR [bp]
diff --git a/gas/testsuite/gas/i386/x86-64-pseudos.d b/gas/testsuite/gas/i386/x86-64-pseudos.d
index d5f4e057119..0fb18a33696 100644
--- a/gas/testsuite/gas/i386/x86-64-pseudos.d
+++ b/gas/testsuite/gas/i386/x86-64-pseudos.d
@@ -315,6 +315,12 @@ Disassembly of section .text:
  +[a-f0-9]+:	41 0f 28 10          	movaps \(%r8\),%xmm2
  +[a-f0-9]+:	40 0f 38 01 01       	rex phaddw \(%rcx\),%mm0
  +[a-f0-9]+:	41 0f 38 01 00       	phaddw \(%r8\),%mm0
+ +[a-f0-9]+:	8a 45 00             	mov    0x0\(%rbp\),%al
+ +[a-f0-9]+:	8a 45 00             	mov    0x0\(%rbp\),%al
+ +[a-f0-9]+:	8a 85 00 00 00 00    	mov    0x0\(%rbp\),%al
+ +[a-f0-9]+:	67 8a 45 00          	mov    0x0\(%ebp\),%al
+ +[a-f0-9]+:	67 8a 45 00          	mov    0x0\(%ebp\),%al
+ +[a-f0-9]+:	67 8a 85 00 00 00 00 	mov    0x0\(%ebp\),%al
  +[a-f0-9]+:	c4 e1 78 28 d7       	vmovaps %xmm7,%xmm2
  +[a-f0-9]+:	c4 e1 78 28 d7       	vmovaps %xmm7,%xmm2
  +[a-f0-9]+:	c4 e1 78 29 fa       	vmovaps %xmm7,%xmm2
@@ -353,4 +359,10 @@ Disassembly of section .text:
  +[a-f0-9]+:	41 0f 28 10          	movaps \(%r8\),%xmm2
  +[a-f0-9]+:	40 0f 38 01 01       	rex phaddw \(%rcx\),%mm0
  +[a-f0-9]+:	41 0f 38 01 00       	phaddw \(%r8\),%mm0
+ +[a-f0-9]+:	8a 45 00             	mov    0x0\(%rbp\),%al
+ +[a-f0-9]+:	8a 45 00             	mov    0x0\(%rbp\),%al
+ +[a-f0-9]+:	8a 85 00 00 00 00    	mov    0x0\(%rbp\),%al
+ +[a-f0-9]+:	67 8a 45 00          	mov    0x0\(%ebp\),%al
+ +[a-f0-9]+:	67 8a 45 00          	mov    0x0\(%ebp\),%al
+ +[a-f0-9]+:	67 8a 85 00 00 00 00 	mov    0x0\(%ebp\),%al
 #pass
diff --git a/gas/testsuite/gas/i386/x86-64-pseudos.s b/gas/testsuite/gas/i386/x86-64-pseudos.s
index 1bd88181212..3b3638cf750 100644
--- a/gas/testsuite/gas/i386/x86-64-pseudos.s
+++ b/gas/testsuite/gas/i386/x86-64-pseudos.s
@@ -320,6 +320,14 @@ _start:
 	{rex} phaddw (%rcx),%mm0
 	{rex} phaddw (%r8),%mm0
 
+	movb (%rbp),%al
+	{disp8} movb (%rbp),%al
+	{disp32} movb (%rbp),%al
+
+	movb (%ebp),%al
+	{disp8} movb (%ebp),%al
+	{disp32} movb (%ebp),%al
+
 	.intel_syntax noprefix
 	{vex3} vmovaps xmm2,xmm7
 	{vex3} {load} vmovaps xmm2,xmm7
@@ -359,3 +367,11 @@ _start:
 	{rex} movaps xmm2,XMMWORD PTR [r8]
 	{rex} phaddw mm0,QWORD PTR [rcx]
 	{rex} phaddw mm0,QWORD PTR [r8]
+
+	mov al, BYTE PTR [rbp]
+	{disp8} mov al, BYTE PTR [rbp]
+	{disp32} mov al, BYTE PTR [rbp]
+
+	mov al, BYTE PTR [ebp]
+	{disp8} mov al, BYTE PTR [ebp]
+	{disp32} mov al, BYTE PTR [ebp]