From f705f9b2751a251f3418c8ff012f796df8f0a084 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Sat, 24 May 2014 08:00:01 -0400
Subject: [PATCH] Fix C compiler interpreting signing, bug773.

---
 Changes                         |  2 ++
 src/V3EmitC.cpp                 |  5 +++--
 test_regress/t/t_math_signed5.v | 14 +++++++++++---
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/Changes b/Changes
index 4f3de61d1..8256ec084 100644
--- a/Changes
+++ b/Changes
@@ -11,6 +11,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ****  Fix shift corner issues, bug765, bug766, bug768, bug772. [Clifford Wolf]
 
+****  Fix C compiler interpreting signing, bug773. [Clifford Wolf]
+
 ****  Fix gate primitives with arrays and non-arrayed pins.
 
 ****  Fix ENDLABEL warnings on escaped identifiers.
diff --git a/src/V3EmitC.cpp b/src/V3EmitC.cpp
index 8df3850cd..3c0e2e9a2 100644
--- a/src/V3EmitC.cpp
+++ b/src/V3EmitC.cpp
@@ -622,8 +622,9 @@ public:
 	    // Only 32 bits - llx + long long here just to appease CPP format warning
 	    if (num<10) puts(cvtToStr(num));
 	    else ofp()->printf("0x%" VL_PRI64 "x", (vluint64_t)num);
-	    //Unneeded-Causes %lx format warnings:
-	    //  if (!nodep->num().isSigned() && (num & (1UL<<31))) puts("U");
+	    // If signed, we'll do our own functions
+	    // But must be here, or <= comparisons etc may end up signed
+	    puts("U");
 	}
     }
     void emitSetVarConstant(const string& assignString, AstConst* constp) {
diff --git a/test_regress/t/t_math_signed5.v b/test_regress/t/t_math_signed5.v
index 26740b20f..c45e92bfd 100644
--- a/test_regress/t/t_math_signed5.v
+++ b/test_regress/t/t_math_signed5.v
@@ -5,6 +5,11 @@
 
 `define checkh(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got='h%x exp='h%x\n", `__FILE__,`__LINE__, (gotv), (expv)); fail='1; end while(0)
 `define checkf(gotv,expv) do if ((gotv) !== (expv)) begin $write("%%Error: %s:%0d:  got=%f exp=%f\n", `__FILE__,`__LINE__, (gotv), (expv)); fail='1; end while(0)
+`ifdef VERILATOR
+ `define c(v,vs) ($c(vs))  // Don't constify a value
+`else
+ `define c(v,vs) (v)
+`endif
 
   module t (/*AUTOARG*/);
 
@@ -127,9 +132,7 @@
       w4_s = 4'sd4;
       w4_u = $signed(5'd1 > w4_s-w4_s);
       `checkh(w4_u, 4'b1111);
-`ifdef VERILATOR
-      w4_s = $c4("4");  // Eval at runtime
-`endif
+      w4_s = `c(4,"4");  // Eval at runtime
       w4_u = $signed(5'd1 > w4_s-w4_s);
       `checkh(w4_u, 4'b1111);
 
@@ -139,6 +142,11 @@
       `checkh(w4_s, 4'bxxxx);
 `endif
 
+      // bug773
+      w5_u = `c(31, "31");
+      w5_s = w5_u >> ((w5_u ? 1 : 2) << w5_u);
+      `checkh(w5_s, 5'b0);
+
       if (fail) $stop;
       $write("*-* All Finished *-*\n");
       $finish;