Use add32ri8 and friends on fast isel.

This fixes pr22854.

The core issue on the bug is that there are multiple instructions that
print the same in assembly. In fact, there doesn't seem to be any
syntax for specifying that a constant that fits in 8 bits should use a 32 bit
immediate.

The attached patch changes fast isel to consider i16immSExt8,
i32immSExt8, and i64immSExt8. They were disabled because fastisel didn’t know
to call the predicate back in the day.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232223 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86InstrInfo.td b/lib/Target/X86/X86InstrInfo.td
index 13bfe2dc270e59afac2dda8911249c9ccf75f3c3..e9a04318be3917a8759cd77c2e9c3ef92fee8609 100644 (file)
--- a/lib/Target/X86/X86InstrInfo.td
+++ b/lib/Target/X86/X86InstrInfo.td
@@ -855,11 +855,11 @@ def X86_COND_E_OR_NE : ImmLeaf<i8, [{
   return (Imm == X86::COND_E) || (Imm == X86::COND_NE);
 }]>;
 
-let FastIselShouldIgnore = 1 in { // FastIsel should ignore all simm8 instrs.
-  def i16immSExt8  : ImmLeaf<i16, [{ return Imm == (int8_t)Imm; }]>;
-  def i32immSExt8  : ImmLeaf<i32, [{ return Imm == (int8_t)Imm; }]>;
-  def i64immSExt8  : ImmLeaf<i64, [{ return Imm == (int8_t)Imm; }]>;
-}
+
+def i16immSExt8  : ImmLeaf<i16, [{ return Imm == (int8_t)Imm; }]>;
+def i32immSExt8  : ImmLeaf<i32, [{ return Imm == (int8_t)Imm; }]>;
+def i64immSExt8  : ImmLeaf<i64, [{ return Imm == (int8_t)Imm; }]>;
+
 
 def i64immSExt32 : ImmLeaf<i64, [{ return Imm == (int32_t)Imm; }]>;
 

diff --git a/test/CodeGen/X86/add32ri8.ll b/test/CodeGen/X86/add32ri8.ll
new file mode 100644 (file)
index 0000000..a74c372
--- /dev/null
+++ b/test/CodeGen/X86/add32ri8.ll
@@ -0,0 +1,10 @@
+; RUN: llc -mtriple=x86_64-linux -fast-isel -show-mc-encoding < %s | FileCheck %s
+
+; pr22854
+; CHECK: addl  $42, %esi               # encoding: [0x83,0xc6,0x2a]
+
+define void @foo(i32 *%s, i32 %x) {
+  %y = add nsw i32 %x, 42
+  store i32 %y, i32* %s, align 4
+  ret void
+}

diff --git a/test/DebugInfo/X86/fission-ranges.ll b/test/DebugInfo/X86/fission-ranges.ll
index 625ca9830fd84dd7891e2d01abaefa2c1a9e0469..a4c10fe1673dc76f105e490d6446e9f96563507f 100644 (file)
--- a/test/DebugInfo/X86/fission-ranges.ll
+++ b/test/DebugInfo/X86/fission-ranges.ll
@@ -25,7 +25,7 @@
 ; if they've changed due to a bugfix, change in register allocation, etc.
 
 ; CHECK: [[A]]: Beginning address index: 2
-; CHECK-NEXT:                    Length: 190
+; CHECK-NEXT:                    Length: 179
 ; CHECK-NEXT:      Location description: 11 00
 ; CHECK-NEXT: {{^$}}
 ; CHECK-NEXT:   Beginning address index: 3